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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Alan Stern <stern@rowland.harvard.edu>,
	David Laight <David.Laight@aculab.com>,
	Jiri Kosina <jikos@kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>, Tejun Heo <tj@kernel.org>,
	Lai Jiangshan <jiangshanlai@gmail.com>,
	Benjamin Tissoires <benjamin.tissoires@redhat.com>,
	Paul McKenney <paulmck@linux.vnet.ibm.com>,
	Andy Lutomirski <luto@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	USB list <linux-usb@vger.kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>
Subject: Re: [PATCH] usbhid: Fix lockdep unannotated irqs-off warning
Date: Mon, 27 Jun 2016 13:36:40 -0700	[thread overview]
Message-ID: <CA+55aFzR8VjVS1XpkJT33-8Mq97QeUAg=YzuQVr8t-7ikJkUjA@mail.gmail.com> (raw)
In-Reply-To: <CA+icZUXDdWmW12hdug=Pr3OMontf6XckrA9ZkP3=C6FE=R1yMA@mail.gmail.com>

On Mon, Jun 27, 2016 at 1:27 PM, Sedat Dilek <sedat.dilek@gmail.com> wrote:
>
> I just grepped for some "buzzwords" people gave me in this
> email-thread and I was looking at (llvm.git HEAD - upcoming v3.9
> release) and found these comments in [1]
>
>
> [1] https://github.com/llvm-mirror/llvm/blob/master/lib/Target/X86/X86InstrInfo.cpp#L4516

Christ. That's still pretty bad. Using LAHF/SAHF is just wrong.

But at least it's not semantically buggy any more, it's just stupid and slow.

Apparently the problem is that LLVM doesn't actually track flags as
different conditions, but as a single register, and doesn't know which
bits of it matter.

I guess the SETO + LAHF/SAHF is the best llvm can do then. But it
doesn't speak well of the code generation quality.

                Linus

  reply	other threads:[~2016-06-27 20:36 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-07 15:59 [PATCH] usbhid: Fix lockdep unannotated irqs-off warning Sedat Dilek
2016-03-07 16:28 ` Sedat Dilek
2016-03-07 16:41 ` Alan Stern
2016-03-07 17:03   ` Steven Rostedt
2016-03-07 17:05   ` Jiri Kosina
2016-03-07 17:15     ` Sedat Dilek
2016-03-07 17:27       ` David Laight
2016-03-07 18:07         ` Alan Stern
2016-03-07 18:30           ` Linus Torvalds
2016-06-27 19:50             ` Sedat Dilek
2016-06-27 20:03               ` Sedat Dilek
2016-06-27 20:14               ` Linus Torvalds
2016-06-27 20:27                 ` Sedat Dilek
2016-06-27 20:36                   ` Linus Torvalds [this message]
2016-03-07 17:11   ` Steven Rostedt
2016-03-07 17:18   ` Sedat Dilek
2016-03-07 17:24     ` Jiri Kosina
2016-03-07 17:30       ` Steven Rostedt
2016-03-07 18:04         ` Andy Lutomirski
2016-03-07 19:10           ` Steven Rostedt
  -- strict thread matches above, loose matches on Subject: below --
2015-09-28  8:10 Sedat Dilek
2015-09-28 11:33 ` Jiri Kosina
2015-09-29  8:40   ` Sedat Dilek
2015-09-29  9:27     ` Jiri Kosina
2015-09-29 18:54       ` Sedat Dilek
2015-09-29 19:08         ` Steven Rostedt
2015-09-29 19:32           ` Sedat Dilek
     [not found]       ` <CA+icZUWH2vR_vpYu4hCS578U3ssmoiF0pLYUfM-Xo-57e8uN=g@mail.gmail.com>
2015-09-30  6:41         ` Sedat Dilek
2015-09-30  8:50           ` Steven Rostedt
2015-09-30  7:35         ` Jiri Kosina
2015-09-30  8:56           ` Steven Rostedt
2015-09-30  9:46             ` Sedat Dilek
2015-09-30 10:13               ` Steven Rostedt
2015-09-30 10:39                 ` Sedat Dilek
     [not found]                 ` <CA+icZUXSzScTmMgLZwPQq9RMH9cUsD5_iDxKTVuG0rrGqH-8Cw@mail.gmail.com>
2015-10-01  2:01                   ` Steven Rostedt
2015-10-01  5:34                     ` Sedat Dilek
2015-10-01  6:05                     ` Sedat Dilek
     [not found]                       ` <CA+icZUUyaHqHP2v52juhGhoTNS9xX7LT2YxkOppLz6f9Z+FBEA@mail.gmail.com>
     [not found]                         ` <CA+icZUWagGMVNs5gBPRBhYO0LsY2A1hK3KSLabp9ZpDVOTmtig@mail.gmail.com>
2015-10-13  0:57                           ` Steven Rostedt
2016-03-01 10:05                             ` Sedat Dilek
2016-03-01 15:07                               ` Steven Rostedt
2016-03-01 15:17                                 ` Peter Zijlstra
2016-03-02 15:00                                   ` Sedat Dilek
2016-03-02 15:17                                     ` Peter Zijlstra
2016-03-02 15:34                                       ` Sedat Dilek
2016-03-02 15:53                                       ` Sedat Dilek
2016-03-02 15:56                                         ` Steven Rostedt
2016-03-02 16:08                                           ` Sedat Dilek
2016-03-02 16:11                                             ` Sedat Dilek
2016-03-02 16:21                                               ` Sedat Dilek
2016-03-02 16:24                                         ` Peter Zijlstra
2016-03-02 16:35                                           ` Steven Rostedt
2016-03-02 16:42                                             ` Peter Zijlstra
2016-03-02 16:42                                           ` Sedat Dilek
2016-03-02 16:52                                             ` Sedat Dilek
2016-03-01 15:59                               ` Alan Stern
2016-03-02  6:25                                 ` Sedat Dilek
2016-03-04 16:04                                   ` Alan Stern
2016-03-05 22:30                                     ` Sedat Dilek
2016-03-06  8:51                                       ` Sedat Dilek
2016-03-06 17:23                                       ` Alan Stern
2016-03-02  6:36                                 ` Sedat Dilek
2016-03-02  8:34                                   ` Sedat Dilek
2016-03-02  8:37                                     ` Jiri Kosina
2016-03-02  9:11                                       ` Sedat Dilek
     [not found]     ` <CA+icZUX3tJvRor6CbOZFBecTAUZzyWzjLzJSEdb3c12yKRAT3g@mail.gmail.com>
2015-09-29 13:13       ` Steven Rostedt

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